One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,8)(5,6)(9,10,15,16)(11,12,13,14)(17,18,20,22)(19,23,24,21)(26,30)(28,36)(31,33)(34,40)(2,5)(7,8)(9,11,15,13)(10,12,16,14)(17,18)(19,21)(20,22)(23,24)(26,30)(28,36)(31,33)(34,40)(1,3,6,4)(2,7,5,8)(9,12,15,14)(10,11,16,13)(17,18)(19,23)(20,22)(21,24)(25,26,29,30)(27,33,35,31)(28,32,36,37)(34,39,40,38)(1,4,6,3)(2,7,5,8)(9,13,15,11)(10,12,16,14)(17,19)(18,21)(20,24)(22,23)(25,27,29,35)(26,31,30,33)(28,34,36,40)(32,38,37,39)(1,5,6,2)(3,7,4,8)(9,14,15,12)(10,11,16,13)(17,19)(18,21)(20,24)(22,23)(25,28)(26,32)(27,34)(29,36)(30,37)(31,38)(33,39)(35,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.